The army

Many of the army's 380 Challenger 2 main battle tanks are likely to be mothballed, as is much of its other heavy armour and artillery. This includes the AS90 self-propelled long-range howitzer, a weapon that was last used in anger in Basra during the invasion of Iraq in 2003.

Squadrons of older armoured vehicles could also be put out to grass as more robust alternatives with greater capacity to withstand blasts from improvised explosive devices in Afghanistan finally come into service.

The total size of the army, now about 100,000, is unlikely to be reduced significantly until after 2015, which is when the government says its combat role in Afghanistan will end.

Some 20,000 British soldiers who are still based in Germany are likely to come home, but they may have to wait to be put up in abandoned RAF bases in Britain.

The navy

The navy would like up to 18 new frigates but this could be reduced to just six. A number of its minesweepers are at risk as is its amphibious capability despite their potential importance in future expeditionary and humanitarian operations. For example, the number of Albion-class landing platform dock vessels in service and the Royal Fleet Auxiliary's Bay-class landing ship docks could be reduced. Question marks remain over what aircraft will be based on the navy's planned new carriers, with Harriers possibly having to fill the gap left by delays in the US F35 Joint Strike Fighters.

It also remains unclear what helicopters the navy will have after the ageing Sea Kings and Lynxes are withdrawn from service. The future of the Devonport dockyard in Plymouth also remains uncertain, according to defence officials. A plan to merge the Royal Marines with the Parachute Regiment has been abandoned.

The RAF

The entire fleet – eight squadrons – of the RAF's two-crew Tornado GR4 strike aircraft, which have been active in Afghanistan, is expected to be withdrawn from service in the bundle of cuts to be announced next week.

The plan to buy an extra 48 Eurofighter Typhoons is also expected to be dropped, leaving the RAF with a total of 160.

The Nimrod MRA4 maritime reconnaissance aircraft could also be at risk. The RAF originally planned to acquire 21 aircraft, then cut the number to nine after a series of delays, cost overruns, and manufacturing problems.

The Nimrods, if kept, could be moved from Kinloss in the north of Scotland, to Waddington in Lincolnshire, described by the International Institute for Strategic Stuides as "the hub of the air force's intelligence, surveillance and reconnaissance operations".

The RAF's total aircraft fleet may be cut from 760 to 550 over the next 10 years.